This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
As will be appreciated, oil and natural gas have a profound effect on modern economies and societies. In order to meet the demand for such natural resources, numerous companies invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are employed to access and extract the resource. These systems can be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly that is used to extract the resource. These wellhead assemblies include a wide variety of components and/or conduits, such as various control lines, casings, valves, and the like, that are conducive to drilling and/or extraction operations. In drilling and extraction operations, in addition to wellheads, various components and tools are employed to provide for drilling, completion, and the production of mineral resources. For instance, during drilling and extraction operations seals and valves are often employed to regulate pressures and/or fluid flow.
A wellhead system may include a various support structures, such as a casing spool or bowl or a tubing head or bowl, configured to secure and support tubing and casing suspended in the well bore. Additionally, a wellhead system may include pressure control and regulation devices, such as a “Christmas tree” or a blowout preventer (BOP). The blowout preventer can be used a primary or back-up pressure regulation device, and often prevents high-pressure release of oil, gas or other fluids in the well in the case of an overpressure condition. During the course of drilling or operating the well, it may be desirable to switch between different sizes of blowout preventers or pressure regulation devices. In such instances, the well is generally plugged or sealed in some manner so that oil, gas, or other fluids are contained within the well when the system's pressure regulation device is disengaged.
Typically, a plug may be used in the casing spool or bowl (or in the tubing spool or bowl) to plug the well, or a backpressure valve may be used to relieve any pressure building up in the well. The plug may be installed before removal of a pressure regulation device, and then retrieved once another pressure regulation device is in place, using a retrieval tool, for example. In such instances, installation or removal of the plug may result in accidental release of pressure from the well, causing the plug to eject from the casing spool or bowl and exit the wellhead, for example. An accidental release may damage the plug or the wellhead, and may also result in the unintentional release of oil, gas, or other fluids in the well. Another challenge may include an attempt to equalize the pressure across the plug to prevent such a blowout or ejection of the plug. However, it may be difficult to accomplish such an equalization, and any unequal pressure may still allow the plug to potentially eject from the wellhead. Additionally, some wells may not be amendable to use of a back pressure valve, such as those using an annular blowout preventer. As a result, use of a plug may be used to seal these wells despite the various challenges and drawbacks. Further, the use of devices or techniques to allow safe installation and/or removal of the plug may introduce increased complexity and cost, and result in multiple trips into the wellhead.